Determination of bacitracin in animal feeds that contain copper

Abstract

A modification of the method involving the use of acidified methanol for the analysis of animal feeds that contain bacitracin and copper sulphate as additives has been developed. Because of the interference of copper in the bacitracin assay, the copper is precipitated by the addition of 3 to 4 mol of sulphide ions per mole of copper. The method has been used for feed samples that contain 5 to 20 p.p.m. of bacitracin and 100 to 300 p.p.m. of copper